Under Section 23 par. 2 (f) of the Act of the National Council of the Slovak Republic No. 541/2004 Coll. on the peaceful use of nuclear energy (the Atomic Act) and on amendments to certain laws as amended, /2/ the licence holder is required to periodically assess, verify and where practicable, systematically and in a verifiable manner increase the level of nuclear safety of nuclear installations during their operation and during decommisioning, and to conduct, at least every ten years, periodic, comprehensive and systemic nuclear safety assessment of nuclear installations (hereinafter as the "Periodic Assessment"), taking into account the current level of knowledge in the field of nuclear safety assessment and to take measures to eliminate identified deficiencies and to eliminate their occurence in the future; this includes also verification that measures are in place to prevent accidents and mitigate the consequences of accidents, including the verification of the application of defence in-depth principles.
Intervals and the scope of the periodic assessment under Section 23 par. 2 (g) of the Atomic Act are laid down in the Decree of thr Nuclear Regulatory Authority of the Slovak Republic No. 33/2012 Coll. on periodic, comprehensive and systematic nuclear safety assessment of nuclear installations as amended by the Decree No. 106/2016 Coll. /3/.
The purpose of the periodic assessment is to determine the extent, to which a given nuclear installation meets current national requirements and international safety standards, and is in line with the good engineering practice. The review avaluates nuclear installations according to the current requirements, examines the cumulative effects of aging of the nuclear installation, the impact of its modifications and the use of operational experience and technical development in the nuclear safety. The review also identifies justified modifications to the nuclear facility in order to maintain or increase the required high level of nuclear safety to the level approaching the level of modern nuclear facilities in the world. At the same time, it is necessary to determine whether the removal of negative findings identified during the review and the implementation of proposed safety improvements will ensure the maintenance of the required level of safety until the next periodic assessment or until the expiry of the authorization issued by the UJD SR.
In 2013, the amendment to the Atomic Act No. 143/2013 Coll. set a permit for the operation of all nuclear installations for an unlimited period (previously limited to a maximum of 10 years). The condition of periodic assessment after 10 years of operation remains valid.